In just two days, the new public advocate’s outrageous behavior has made a slam-dunk case for the argument The Post has been making for decades: The public advocate is New York City’s most useless job — and it ought to be abolished.

We’ve always said that the only real service the office provides is a soapbox for grabbing attention and making mischief. Which is precisely what Letitia James has been doing.

On New Year’s Day, she delivered an inaugural address so over-the-top that it distinguished itself amid a long afternoon of speeches so distasteful that even The New York Times called them “graceless and smug” — adding that James was the “worst among them.”

One reason for this is that our new public advocate contrived to steal the spotlight by attaching herself to 12-year-old Dasani Coates. Coates lives with her family in a shelter in James’ former council district, and was recently the subject of a lengthy Times series on homelessness.

It wasn’t enough for James to make Dasani the centerpiece of her swearing in. Or to claim the girl as her new “BFF.” James also boasted in interviews she was responsible for the Times’ series.

In her own words, James said she “decided to basically put on the front page of The New York Times the face of poverty in the city of New York.”

Which brought another sharp slap-down from the same paper. James was never interviewed and she wasn’t a source for the series, the Times’ assistant managing editor said in a statement. That led James to backtrack, even while claiming she “did not intend to imply” she’d been a source.

Well, that’s two for two in her first days in office — and she’s got four long years to go. We may no longer have to advocate for abolishing her office. We suspect the outrages of Letitia James will make our case for us.